It is a known problem that the disposal of various wastes, for example used rubber tyres, puts a heavy burden on the environment. Therefore, a number of solutions have been worked out for recycling scrap rubber tyres in a way that they can be used for extracting materials worth using further. One of the most suitable methods to do so is pyrolysis, which is carried out on whole or shredded rubber tyres according to the prior art.
By way of example, reactors and apparatuses for pyrolysing of rubber tyres and in the given case other wastes are described in U.S. Pat. No. 3,997,407, U.S. Pat. No. 4,846,082, U.S. Pat. No. 5,060,584, U.S. Pat. No. 5,595,483, U.S. Pat. No. 6,048,374, EP 0 532 901 A1, EP 1 462 505 B1 and WO 2005/047435 A2. These known solutions comprise rotary stirring components and fluidised bed approaches for enabling a smooth pyrolysis. The disadvantage of stirring components is that they substantially increase the building and operating costs of the reactor, and furthermore that they entangle the wire sections in the unshredded and shredded rubber tyres, thereby causing a blockage in the pyrolysis space. A disadvantage of the fluidised bed approach is that a relatively high rate of heating medium flow must be provided, and furthermore that due to intensive agitation, the wire tangle problem arises here, too.
In the known reactors, the material intended to be incinerated or pyrolysed is in a continuous motion, as a result of which substantial temperature differences amounting to eventually several hundred degrees arise in the material. Due to the constant and uncontrolled internal movement, in the case of rubber waste reinforced with steel wire cord, large ‘balls’ are generated from the wires, and their removal from the system represents a difficult problem. A further disadvantage is the requirement of a very high temperature, which may even be higher than 1000° C., and this necessitates the application of very costly structural materials. A further problem is that the period in which waste scraps stay in the apparatus and the resulting rate of temperature changes are occasional—may even be very short or very long—in the various temperature zones (preheating, pyrolysis, oxidation). Therefore, the chemical composition of the generated gas/steam cannot be controlled.